Thorunna kahuna
Johnson & Gosliner, 2001

Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: EUDORIDOIDEA
Family: Chromodorididae

DISTRIBUTION

Known only from Midway and Hawaiian Ids.

PHOTO

Midway Atoll. On pier pilings at 5 meters, 10 April 2000. Photo: Keoki Stender.

The animal is translucent with a pinkish purple tinge, and appears white from the colour of the internal organs. There is a thin submarginal reddish-pink to purple line around the mantle. There is a similar coloured submarginal line around the posterior part of the foot. Around the posterior end of the mantle there is a very distinctive opaque white band of mantle glands, and at the anterior end of the mantle, there are clusters of 3 or 4 similar glands at the edge of the mantle, on each side, in front of the rhinophores. The rhinophore clubs are translucent orange. The gills are translucent white at the base and the upper two-thirds is translucent orange.

In shape and colour Thorunna kahuna is very similar to Thorunna daniellae. According to Johnson & Gosliner (2001) "the most distinct external difference between T. daniellae and T. kahuna is the presence of large, visible mantle glands on the sides of the head anterior to the rhinophores and posterior to the gills in T. kahuna." If glands are present in T. daniellae they are not visible with the naked eye. Thorunna kahuna and T. daniellae also have different radular teeth, with those of T. kahuna having many more denticles than those of T. daniellae. Interestingly, the only two species of Thorunna with visible mantle glands, T. kahuna and T. australis also have very denticulated teeth. Another two differences between T. daniellae and T. kahuna concern the gills. In T. kahuna, the whole of the upper gill is suffused with orange while in T. daniellae, the orange pigment seems restricted to an orange line up the outer edge of the gills. Like most species of Thorunna, this species rhythmically vibrates its gills [see Keoki Stender's message].

See Radular morphology

References:
• Johnson, R.F. & Gosliner, T.M. (2001) Two new species of Thorunna Bergh 1878 (Mollusca: Nudibranchia: Chromodorididae) from the Indo-Pacific. Bollettino Malacologico, 37(5-8): 143-150.

Authorship details
Rudman, W.B., 2003 (October 1) Thorunna kahuna Johnson & Gosliner, 2001. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/thorkahu

Related messages

  1. Re: Thorunna kahuna from Midway
    From: Keoki Stender, October 5, 2003
  2. Re: Thorunna daniellae from Midway
    From: Keoki Stender, October 4, 2003
  3. Thorunna kahuna and T. daniellae
    From: Rebecca F. Johnson, October 4, 2003
  4. Radula of Thorunna kahuna
    From: Rebecca Johnson, October 4, 2003
  5. Thorunna daniellae from Midway
    From: Keoki Stender, October 1, 2003

Show factsheet and all related messages